U.S. patent application number 11/837982 was filed with the patent office on 2009-02-19 for capacitive detection of dust accumulation using microcontroller component leads.
This patent application is currently assigned to INTERNATIONAL BUSINESS MACHINES CORPORATION. Invention is credited to Justin Potok Bandholz, Zachary Benson Durham, Clifton Ehrich Kerr, Joseph Eric Maxwell, Kevin Michael Reinberg, Kevin S. Vernon, Philip Louis Weinstein, Christopher Collier West.
Application Number | 20090045967 11/837982 |
Document ID | / |
Family ID | 40362538 |
Filed Date | 2009-02-19 |
United States Patent
Application |
20090045967 |
Kind Code |
A1 |
Bandholz; Justin Potok ; et
al. |
February 19, 2009 |
CAPACITIVE DETECTION OF DUST ACCUMULATION USING MICROCONTROLLER
COMPONENT LEADS
Abstract
A system and method are used for electronically detecting the
accumulation of dust within a computer system using a capacitive
dust sensor. The dust detection system may be implemented on a
smaller computer, such as an individual PC, or in a more expansive
system, such as a rack-based server system ("rack system") having
multiple servers and other hardware devices. In one embodiment,
each server in a rack system includes a capacitive sensor
responsive to the accumulation of dust. The capacitive sensor may
include one or more capacitive plates integral with a heatsink. As
dust collects on the capacitive plates, the capacitance increases.
When a capacitance setpoint is reached, indicating the dust has
reached a critical level, an alert is generated. The alerts may be
received by a management console for the attention of a system
administrator. Each alert may contain the identity of the server
generating the alert, so that the system administrator knows which
server(s) are to be removed for cleaning.
Inventors: |
Bandholz; Justin Potok;
(Cary, NC) ; Durham; Zachary Benson; (Asheboro,
NC) ; Kerr; Clifton Ehrich; (Durham, NC) ;
Maxwell; Joseph Eric; (Cary, NC) ; Reinberg; Kevin
Michael; (Durham, NC) ; Vernon; Kevin S.;
(Durham, NC) ; Weinstein; Philip Louis; (Apex,
NC) ; West; Christopher Collier; (Raleigh,
NC) |
Correspondence
Address: |
IBM CORPORATION (SS/NC);c/o STREETS & STEELE
13831 NORTHWEST FREEWAY, SUITE 355
HOUSTON
TX
77040
US
|
Assignee: |
INTERNATIONAL BUSINESS MACHINES
CORPORATION
Armonk
NY
|
Family ID: |
40362538 |
Appl. No.: |
11/837982 |
Filed: |
August 13, 2007 |
Current U.S.
Class: |
340/627 |
Current CPC
Class: |
G01N 15/0656
20130101 |
Class at
Publication: |
340/627 |
International
Class: |
G08B 21/00 20060101
G08B021/00 |
Claims
1. A dust detection system for detecting the accumulation of dust
in an air-cooled hardware device, comprising: a device housing
having an air inlet and an air outlet; an airflow source for
generating airflow through the device housing from the air inlet to
the air outlet; and a microcontroller disposed in the device
housing, the microcontroller including a plurality of input leads
and a built-in capacitance sensor configured for generating a
signal in relation to the capacitance between at least two of the
input leads, wherein the capacitance sensor is sensitive to
accumulation of dust between the at least two input leads.
2. The dust detection system of claim 1, wherein the
microcontroller is configured for generating the signal in response
to the value of the capacitance between the at least two input
leads reaching or exceeding a capacitance setpoint.
3. The dust detection system of claim 1, wherein the signal
comprises illumination of a light emitting diode or a service
processor event message.
4. The dust detection system of claim 1, wherein the at least two
input leads associated with the capacitance sensor are spaced
within about 1 millimeter.
5. The dust detection system of claim 1, wherein the at least two
input leads associated with the capacitance sensor are positioned
upstream of the body of the microcontroller with respect to a
direction of airflow from the airflow inlet to the airflow outlet
of the device housing.
6. The dust detection system of claim 1, wherein the air-cooled
hardware device comprises an air-cooled server removably insertable
into a multi-server chassis.
7. The dust detection system of claim 6, further comprising a
management module disposed in the chassis and in communication with
the server for receiving the signal and identifying the hardware
device.
8. The dust detection system of claim 1, further comprising a
raised portion about the at least two input leads for trapping dust
on the at least two input leads.
9. The dust detection system of claim 8, wherein the raised portion
is substantially U-shaped, with an open end of the U-shaped
projection is positioned upstream from a closed end of the U-shaped
projection.
10. The dust detection system of claim 1, wherein electrically
conducting portions of the at least two input leads are exposed to
the airflow, and the other of the plurality of input leads are
electrically insulated from airflow.
11. A method of detecting dust within a hardware device,
comprising: generating airflow through a housing of the hardware
device; sensing the capacitance between at least two input leads of
a microcontroller disposed within the hardware device; detecting a
change in capacitance between the at least two leads consistent
with the deposition of dust between the leads; and generating a
signal responsive to the change in capacitance.
12. The method of claim 11, further comprising generating the
signal in response to the capacitance reaching or exceeding a
setpoint.
13. The method of claim 12, further comprising generating an alert
in response to reaching or exceeding the capacitance setpoint.
14. The method of claim 13, wherein generating the alert comprises
illuminating an LED or generating a service processor event
message.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to the detection and removal
of dust in electronic systems.
[0003] 2. Description of the Related Art
[0004] Airflow is commonly used to remove heat generated by
components within a computer. For example, an individual PC
typically includes one or more on-board cooling fans enclosed
within the housing to cool the processors, power supply, memory,
and other internal components. In more expansive computer systems,
such as rack-based blade computer systems having multiple servers,
one or more blower modules are supported on a multi-server chassis
to generate airflow through the servers and other components.
Despite efforts to keep a computer center clean and filter dust out
of the air, the airflow used to cool a computer carries some amount
of dust, which accumulates over time on internal components of the
computer. The electrostatic charge generated by some components can
even attract dust to those components, thereby increasing the
amount and rate of dust deposited.
[0005] Unfortunately, the accumulation of dust in a computer system
can cause problems. Excessive dust build-up can reduce system
performance, increase the rate at which components fail, and reduce
overall system reliability. Dust can also interfere with operation
of moving parts, such as fan blades and mechanical connectors, and
reduce the reliability of electrical components, such as by
collecting between electrical contacts in electrical connectors.
Dust can even give off an unpleasant odor when heated through
contact with hot components.
[0006] The amount of dust that accumulates in a hardware device is
typically not apparent without removing it and opening it up.
Manually inspecting hardware for dust is inefficient, usually
necessitating the removal of the hardware from the chassis. In many
cases, the system must be off line for a person to physically
disassemble and clean out the system. An improved dust detection
system and method are therefore needed. Improvements in the speed
and ease of detecting dust accumulation would be especially
desirable in larger computer systems such as rack systems having
numerous servers and other hardware components. It would be
particularly desirable to have a system and method that would
automatically detect the accumulation of dust.
SUMMARY OF THE INVENTION
[0007] The present invention provides systems and methods for
detecting dust within an electronic system, such as within a
computer system.
[0008] One embodiment provides a dust detection system for
detecting the accumulation of dust in an air-cooled hardware
device. A device housing includes an air inlet and an air outlet.
An airflow source is configured for generating airflow through the
device housing from the air inlet to the air outlet. A
microcontroller disposed in the device housing includes a plurality
of input leads and a built-in capacitance sensor configured for
generating a signal in relation to the capacitance between at least
two of the input leads. The capacitance sensor is sensitive to
accumulation of dust between the at least two input leads.
[0009] Another embodiment provides a method of detecting dust
within a hardware device. Airflow is generated through a housing of
the hardware device. The capacitance between at least two input
leads of a microcontroller disposed within the hardware device is
sensed. A change in capacitance is detected between the at least
two input leads consistent with the deposition of dust between the
leads. A signal is generated responsive to the change in
capacitance.
[0010] Other embodiments, aspects, and advantages of the invention
will be apparent from the following description and the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a front elevation view of a conventional rack
system having a plurality of blade servers in which a dust
detection system and method may be implemented.
[0012] FIG. 2 is a side elevation view of one of the blade servers
with an outer housing removed to reveal a dust-sensing
microcontroller for sensing dust within the blade server.
[0013] FIG. 3 is a schematic diagram of the dust-sensing
microcontroller.
[0014] FIG. 4 is a schematic diagram of a portion of the
microcontroller that includes the capacitance sensor coupled to two
of the input leads.
[0015] FIG. 5 is a graph of the relationship between dust
accumulation and capacitance.
[0016] FIG. 6 is a schematic diagram of a portion of the
microcontroller that includes a U-shaped projection for trapping
dust on the capacitive input leads.
[0017] FIG. 7 is a flowchart generally outlining a method of
detecting dust in a hardware device using a capacitive-sensing
microcontroller.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0018] The present invention provides a system and method for
electronically detecting the presence of dust within a computer
system using a microcontroller ("chip") having built-in capacitive
sensing technology. One of the chips customarily included with a
computer system, such as the CPU, Ethernet Controller, Memory
Controller, IO Controller, or Video Controller, may be modified or
re-designed to include a capacitive-sensing subsystem.
Alternatively, a separate chip having built-in capacitive sensing
technology could be added to an existing system configuration. The
dust detection system may be implemented in a stand-alone computer,
such as an individual PC, or in a more expansive system, such as a
rack-based blade server system ("rack system") having multiple
blade servers and other hardware devices. The chip is configured to
detect a change in capacitance consistent with the accumulation of
dust. When the capacitance reaches a setpoint, the chip generates
an alert. This provides automatic detection of dust within a
computer system so that hardware need not be manually inspected for
dust. This saves time and money, and wear and tear on components
such as device connectors.
[0019] In one embodiment, each server in a rack system may receive
one of the chips having a capacitive sensing subsystem. Each chip
is placed on a motherboard of the respective server, in the path of
the airflow through the server. Firmware is provided to enable the
detection of capacitance changes caused by dust accumulation. Each
chip monitors the capacitance between two adjacent input leads
(which may be pins or terminals) on the chip, and is sensitive to
changes in capacitance as dust accumulates between the adjacent
input leads. The leads are spaced within about 1 mm of each other,
and the chip is oriented with the two adjacent leads upstream of
the body of the chip. In response to reaching or exceeding a
capacitance setpoint, the chip generates an alert, such as
illumination of a light emitting diode (LED) or generation of a
service processor event message. The service processor event
message may be received by a management console for the attention
of a system administrator. Each alert may contain the identity of
the blade server generating the alert, so that the system
administrator knows which blade server(s) need to be cleaned.
Automatically detecting the accumulation of dust in blade servers
or other components saves time, labor, and associated operating
expense as compared with manually removing and individually
inspecting each blade server for dust.
[0020] FIG. 1 is a front elevation view of a conventional,
rack-based computer system ("rack system") 10 in a data center 20.
The rack system 10 is an example of a computer system having a
plurality of blade servers and other air-cooled hardware devices in
which dust will accumulate over time. The rack system 10 includes a
rack 12 supporting six server chassis 14. Each server chassis 14
supports fourteen networked blade servers 16, along with supporting
hardware, such as power supplies, switches, and a management
module. Thus, the rack 12 holds up to eighty-four heat-generating
blade servers and support modules, all of which are air-cooled.
Periodic manual inspection of such a system may be costly and time
consuming, particularly due to the large number of hardware devices
involved.
[0021] Each server chassis 14 supports one or more blower module
known in the art for circulating air through the server chassis 14
to cool the blade servers 16 and support modules within the server
chassis 14. Heated air expelled from the rack system 10 is then
taken up by an air intake 22 and circulated through a computer-room
air-condition system (CRAC) that cools the air and returns it to
the data center 20. As air blows through the blade servers 16 and
other hardware devices, dust collects over time in each of the
hardware devices in the rack system 10. The invention provides
systems and methods for detecting the accumulation of dust in a
blade server 16 or other hardware device without removal.
[0022] A workstation 24 is optionally networked with the blade
servers 16 for helping a system administrator 26 monitor and
control the blade servers 16 globally. The workstation 24 includes
a management console 28, which has a customizable graphical
administrative interface, and a management server 29, which can
remotely control and support several remote computer subsystems
including the blade servers 16. Local software (e.g. a system
"agent") may be installed on each blade server 16, allowing the
management server 29 to selectively interface with the various
blade servers 16 to monitor and control the blade servers 16. For
example, an agent installed on a particular blade server 16 may
send a signal over the network to warn the system administrator 26
that intervention is required for that blade server.
[0023] The workstation 24 may include additional functionality
pertaining to the detection of dust according to the invention, and
that functionality may be tied in to existing features, such as the
ability of the blade servers 16 to generate alerts in the form of
service processor event messages. For example, each blade server 16
may detect the accumulation of dust on its components or within its
housing, as further described below, and generate an alert signal
when the amount of accumulated dust reaches a critical level that
requires servicing the blade server 16. The alert signal may be
received at the workstation 24 and reported by the management
console 28. The system administrator 26 may monitor the management
console 28 to know which specific hardware devices need servicing
for dust removal at any particular time. This approach to
monitoring the accumulation of dust within the individual hardware
devices of the rack system 10 is more efficient than periodically
removing and visually inspecting all the components to determine
which hardware devices need cleaning.
[0024] FIG. 2 is a side elevation view of one of the blade servers
16 adapted to include a capacitive sensing chip 50 configured
according to the invention for the detection of dust within the
blade server 16. Air enters a housing of the blade server 16 at an
air inlet 17 and exits at an air outlet 18. An outer housing wall
has been removed to reveal some of the internal components on which
dust accumulates. Some of the conventional components of the
exemplary blade server 16 include four memory modules (DIMMs) 30,
voltage regulators 32, control chips 34, two small form factor
(SFF) hard drives 36, redundant power and signal connectors 38, and
a pair of processor heatsinks 40 for cooling microprocessors
("CPUs") disposed below the heatsinks 40. The components are
generally mounted on a motherboard 35. Dust accumulates in the
blade server 16 and must be cleaned periodically to avoid problems.
For example, the accumulation of dust reduces airflow between the
fins of the heatsinks 40 and thus reduces the cooling efficiency of
the heatsinks 40. This reduced cooling efficiency can impact the
overall efficiency of the rack system 10, such as by requiring an
increased airflow rate in order to sufficiently cool the blade
servers 16.
[0025] The chip 50 is positioned on the motherboard 35. Dust 52
accumulates throughout the blade server 16, including on the input
leads 54 of the chip 50. The chip 50 is configured for detecting
capacitance changes induced by the accumulation of dust over time.
The chip 50 is positioned on a portion of the motherboard 35 having
plenty of area around the perimeter of the chip 50 unobstructed by
neighboring components, so that dust-carrying airflow readily
reaches the chip and deposits dust on the chip 50 over time. The
dust 52 on the input leads 54 causes a change in capacitance
between selected input leads, and the capacitance between the
selected input leads can be correlated with the extent of dust
accumulation. The chip 50 detects when dust accumulates to an
excessive level, and generates an alert, such as a service
processor event message and/or the illumination of an LED 33 on the
front of the blade server 16.
[0026] FIG. 3 is a schematic diagram of the chip 50. Each side of
the chip 50 includes sixteen input terminals ("leads") 54, although
any number of input leads may be included. The chip 50 may contain
a complex architecture that includes any number of logic circuits
known in the art. Different input leads 54 may be mapped to
different logic circuits for inputting data used by the respective
logic circuits. Among the many circuits that may be included on the
chip 50 is a capacitive-sensing logic circuit outlined at 56, which
is mapped to provide electronic communication with the at least two
input leads 54A and 54B. As airflow passes over the capacitive
input leads 54A, 54B, dust will accumulate between them. While dust
may also accumulate between other input leads 54, the other input
leads may be mapped to other logic circuits that are not associated
with detecting the accumulation of dust.
[0027] FIG. 4 is a further detailed schematic diagram of a portion
of the chip 50 that includes the capacitive input leads 54A, 54B
and the capacitive sensing logic circuit 56 in electronic
communication with the capacitive input leads 54A, 54B. The
capacitive input leads 54A, 54B function as capacitive plates. A
voltage source 58 included with the capacitive-sensing circuit 56
generates an electric field E between the capacitive input leads
54A, 54B. The electric field E results in a net negative charge
"Q-" on the first input lead 54A and a net positive charge "Q+" on
the second input lead 54B. The first and second input leads are
spaced apart at a distance "D" that is preferably no more than
about 1 mm. In many configurations, a spacing of 1 mm will allow
average sized dust particles to induce a detectable change in
capacitance. However, depending on the environment, the spacing may
be greater or less than 1 mm. For example, dust particle size may
vary between different environments, which may affect the spacing
selected for the respective environment to optimize the detection
of the dust particles on or between the capacitive input leads 54A,
54B. However, the voltage available on the chip may also be a
factor in determining a suitable spacing of the leads.
[0028] Sensor firmware 60 may be included with the chip 56 for
monitoring electrical activity at the capacitive input leads 54A,
54B and interpreting the electrical activity as a corresponding
capacitance value or change in capacitance. The firmware 60 is
particularly adapted for detecting changes in capacitance
indicative of the presence of dust. The firmware 60 may have the
ability to differentiate between capacitance changes caused by dust
and capacitance changes caused by other environmental parameters,
such as an accidental short or the placing of a user's finger on
the input leads. For example, the chip 56 may be calibrated to
establish the normal range in capacitance due to dust, so that in
use, the chip 56 is responsive to changes caused by dust.
Capacitance values outside this range may be selectively excluded
from the analysis, or may trigger fault circuitry (not shown) to
generate a fault for the attention of an administrator.
[0029] FIG. 5 is a graph illustrating how capacitance C between the
capacitive input leads 54A, 54B might vary as a function of the
amount of dust that has accumulated. An upwardly sloping curve 62
indicates a general increase in C in response to dust accumulation.
The curve 62 is provided for the purpose of discussion, and an
actual curve characterizing a particular chip may have a different
shape. As dust accumulates, the capacitance C increases from a
finite, non-zero value C.sub.0 prior to the accumulation of any
dust, to a critical capacitance C.sub.CRIT at which the device
should be removed for cleaning. C.sub.CRIT may be selected by a
system designer. C.sub.CRIT may be determined empirically, such as
by using conventional criteria (e.g. conventional visual
indicators) to determine when an excessive amount of dust has
accumulated on a representative motherboard, and setting C.sub.CRIT
as the value of C observed at that dust level.
[0030] C.sub.CRIT may be used in the selection of a setpoint. When
a device having the chip is subsequently placed in service, an
alert may be generated when C reaches or exceeds C.sub.CRIT.
Alternatively, the setpoint may be selected as a capacitance
differential equal to the range "R.sub.C" between C.sub.0 and
C.sub.CRIT, so that an increase in capacitance equal to or greater
than R.sub.C may trigger an alert. However, values significantly
outside the range R.sub.C may indicate something other than the
accumulation of dust. For example, an observed value of C that is
significantly above C.sub.CRIT or below C.sub.0 may indicate the
presence of a foreign object, such as a finger or a short circuit
between capacitive input leads. Special alerts may be generated to
flag an abnormal capacitance reading such as these and
differentiate these alerts from other system alerts generated in
response to reaching or exceeding the capacitance setpoint.
[0031] FIG. 6 is a schematic diagram of a portion of the chip 50
provided in FIG. 4, with some additional features.
Non-participating leads (leads that are not involved in sensing
capacitance) are indicated by hatching. An optional insulating
material may be provided on these non-participating input leads.
The capacitive input leads 54A, 54B (the leads that are involved in
sensing capacitance) are indicated by the absence of hatching. The
capacitive input leads 54A, 54B should be exposed to the flow of
air, so that they are sensitive to the accumulation of dust. An
optional U-shaped projection 70 is also provided about the exposed
capacitive input leads 54A, 54B. The U-shaped projection 70 may
project upwardly (out of the page) up to a few millimeters, and
serves at least two purposes. First, the U-shaped projection 70
protects capacitive input leads 54A, 54B from short circuiting with
adjacent components or becoming physically damaged. Second, the
U-shaped projection 70 helps trap dust on the capacitive input
leads 54A, 54B. The open end 72 of the U-shaped projection 70 is
open to airflow (facing upstream), so that dust may enter the
U-shaped projection 70. The closed end 74 is downstream, for
"trapping" dust. The optional U-shaped projection 70 thereby helps
collect dust over the capacitive input leads 54A, 54B, which may
increase the range R.sub.C between C.sub.0 and C.sub.CRIT (see FIG.
5). The increased range R.sub.C may help the chip 56 discern the
accumulation of dust as it approaches an excesses level. This, in
turn, may provide more reliable alerts. Furthermore, the projection
70 may shield the capacitive input leads 54A, 54B from interference
due to other adjacent leads 54.
[0032] FIG. 7 is a flowchart generally outlining a method for
detecting dust within a hardware device according to the invention.
Airflow is generated in step 80. For example, in a standalone PC,
airflow may be generated by an on-board fan. In a multi-server rack
system, airflow may be generated by a blower module supported on
the multi-server chassis. Capacitance between two input leads of a
chip is monitored in step 82. If a change in capacitance is
detected in step 84, the change is further analyzed. If the change
resulted in the value of C being very far outside the usual range
R.sub.C, such as much greater than C.sub.CRIT or much less than
C.sub.0 as set out in step 86, then some cause other than a gradual
accumulation of dust may be suspected. The anomaly could be a short
circuit of the capacitive input leads, for example. An "alternative
alert" is generated in step 88 to indicate this condition. However,
assuming the value of C has not moved appreciably outside the usual
range, the capacitance may instead be monitored for routine changes
due to the accumulation of dust. Once C reaches or slightly exceeds
C.sub.CRIT, as determined in step 90, then an alert may be
generated in step 92 indicating the accumulation of dust and the
need to service the device for dust removal.
[0033] The above described embodiments are non-limiting examples of
how a dust detection system and method may be implemented, and
other embodiments of capacitive dust sensing are within the scope
of the invention. A dust detection system as shown and described
herein is useful in virtually any electronic system prone to the
accumulation of dust. Almost any electronic system may benefit from
the ability to automatically, electronically detect the
accumulation of dust. Electronic systems having a capacitive dust
detection system according to the invention will require much less
manual, labor-intensive inspection, with an associated reduction in
downtime and maintenance expenses. Electronic systems may be
serviced for dust removal and general cleaning on a more logical,
as-needed basis, rather than as a matter of routine. For example,
system administrators responsible for larger computer systems may
spend less time manually inspecting and servicing blade servers and
other hardware devices, and may instead respond as needed to alerts
individually generated by the blade servers. Thus, system resources
are better allocated to those tasks and devices with a demonstrable
need for attention. Furthermore, since the dust accumulation is
detected using features built into a chip, it is not necessary to
provide additional components in the housing or on the
motherboards.
[0034] The terms "comprising," "including," and "having," as used
in the claims and specification herein, shall be considered as
indicating an open group that may include other elements not
specified. The terms "a," "an," and the singular forms of words
shall be taken to include the plural form of the same words, such
that the terms mean that one or more of something is provided. The
term "one" or "single" may be used to indicate that one and only
one of something is intended. Similarly, other specific integer
values, such as "two," may be used when a specific number of things
is intended. The terms "preferably," "preferred," "prefer,"
"optionally," "may," and similar terms are used to indicate that an
item, condition or step being referred to is an optional (not
required) feature of the invention.
[0035] While the invention has been described with respect to a
limited number of embodiments, those skilled in the art, having
benefit of this disclosure, will appreciate that other embodiments
can be devised which do not depart from the scope of the invention
as disclosed herein. Accordingly, the scope of the invention should
be limited only by the attached claims.
* * * * *